title: Comparative analysis of sex chromosomes in Leporinus species (Teleostei, Characiformes) using chromosome painting.
abstract: BACKGROUND
  The Leporinus genus, belonging to the Anostomidae family, is an interesting model for studies of sex chromosome evolution in fish, particularly because of the presence of heteromorphic sex chromosomes only in some species of the genus. In this study we used W chromosome-derived probes in a series of cross species chromosome painting experiments to try to understand events of sex chromosome evolution in this family.
  
  
  RESULTS
  W chromosome painting probes from Leporinus elongatus, L. macrocephalus and L. obtusidens were hybridized to each others chromosomes. The results showed signals along their W chromosomes and the use of L. elongatus W probe against L. macrocephalus and L. obtusidens also showed signals over the Z chromosome. No signals were observed when the later aforementioned probe was used in hybridization procedures against other four Anostomidae species without sex chromosomes.
  
  
  CONCLUSIONS
  Our results demonstrate a common origin of sex chromosomes in L. elongatus, L. macrocephalus and L. obtusidens but suggest that the L. elongatus chromosome system is at a different evolutionary stage. The absence of signals in the species without differentiated sex chromosomes does not exclude the possibility of cryptic sex chromosomes, but they must contain other Leporinus W sequences than those described here.
authors.affiliation: Departamento de Biologia, Laboratório de Citogenética, Instituto de Biociências, Universidade Estadual Paulista Julio de Mesquita Filho - UNESP, Rio Claro, Av. 24A, 1515, CEP 13506-900 Rio Claro, SP, Brazil. parise@rc.unesp.br
authors.forename: Patrícia Pasquali
authors.initials: PP
authors.lastname: Parise-Maltempi
authors.forename: Edson Lourenço
authors.initials: EL
authors.lastname: da Silva
authors.forename: Willem
authors.initials: W
authors.lastname: Rens
authors.forename: Frances
authors.initials: F
authors.lastname: Dearden
authors.forename: Patricia C M
authors.initials: PC
authors.lastname: O'Brien
authors.forename: Vladimir
authors.initials: V
authors.lastname: Trifonov
authors.forename: Malcolm A
authors.initials: MA
authors.lastname: Ferguson-Smith
mesh_terms: D000818:Animals; D060125:Characiformes / Q000235:genetics*; D005260:Female; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D012730:Sex Chromosomes